Network & Security Support · Deliverable
Network Fault Diagnosis and Root Cause Reports.
Network fault diagnosis reports with root cause analysis
Part of Network & Security Support. Last reviewed October 2026.
Quick answer
What is Network Fault Diagnosis and Root Cause Reports?
A network fault diagnosis report is a written record of how an engineer isolated a connectivity or performance problem, what evidence supports the conclusion, and what fixed it. Deploris engineers inspect the physical layer, analyze packets and device state, apply the agreed fix, and deliver a root cause analysis with prevention recommendations.
WHAT THE WORK COVERS
What Network Fault Diagnosis and Root Cause Reports includes.
- 01Intake of the symptom timeline, affected users and applications, recent changes, and any monitoring alerts already raised
- 02Physical layer inspection of cables, patch panels, SFP optics (including light levels), interface error counters, and duplex or speed mismatches
- 03Logical analysis of VLAN tagging, trunk allowed lists, ARP and MAC tables, routing tables, ACLs, and MTU along the path
- 04Spanning tree review for topology changes, root bridge placement, and loops, with port-level evidence
- 05Packet capture through SPAN ports or inline taps, analyzed in Wireshark, plus SNMP and NetFlow data where you already collect it
- 06DNS, DHCP, and authentication checks (802.1X, RADIUS) when symptoms point to services rather than transport
- 07A written report covering symptoms, tests, root cause, remediation applied, and recommended prevention steps
HOW WE DELIVER IT
How it is delivered.
- 1
Scope the fault
We collect the symptom history, topology, and recent change records, agree what we may capture or change, and decide whether the first move is remote analysis or a site visit.
- 2
Test layer by layer
The engineer works from the physical layer upward, using counters, captures, and path tests to confirm or eliminate each candidate cause with recorded evidence.
- 3
Fix under change control
Once the cause is proven, we apply the remediation through your change process, such as replacing a cable or optic or correcting a trunk or MTU setting, and retest.
- 4
Report and recommend
You receive the root cause analysis with evidence, the fix, and recommendations to reduce the chance of recurrence, and captures are deleted unless you ask for retention.
INPUTS AND OUTPUTS
What you provide and what you receive.
You provide
- A description of the symptoms with times, locations, and affected applications
- Network diagrams, device inventory, and recent change records if they exist
- Read access to switches, routers, and monitoring tools, or an on-site escort to the network closets
- Permission and a window for packet capture, port mirroring, or any remediation change
You receive
- A root cause analysis report with the symptom timeline and the evidence behind the conclusion
- Captured data summaries, interface counters, and test results referenced in the report
- A record of the remediation performed, including before and after measurements
- Prevention recommendations ranked by effort, such as monitoring thresholds or configuration standards
WHEN IT FITS
When this is the right deliverable.
Users report intermittent slowness that your monitoring cannot explain, and you suspect a duplex mismatch, a failing optic, or a spanning tree event.
Point-of-sale or application timeouts affect only some sites, and your team needs someone to capture traffic at the branch edge and examine MTU and routing.
A previous outage was closed with a restart and no explanation, and your auditors or management now want a documented root cause.
WHERE WE DELIVER
Delivered in 75+ metros across 11 countries.
Local, vetted engineers deliver this work on site across the United States and Western Europe, coordinated by one engagement manager.
QUESTIONS
Frequently asked questions.
What does a network root cause analysis report contain?
Can you diagnose network faults remotely before sending an engineer?
How do you capture packets on a production network safely?
What kinds of network problems can field troubleshooting find?
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